This invention relates generally to a method and apparatus for determining the individual phase flow velocities in multiphase flow systems. The invention has particular application in light water nuclear reactors. There are many industrial applications for improved methods of measuring multiphase flow. Such improved methods are needed for the continued development of mathematical models to predict flow fluid parameters in applications such as nuclear reactor systems, heat exchangers in the process industry, safety relief valves and steam generators. They are also needed to verify computer models based on individual phase flow velocities of multiphase media, where the component velocities that are not known, but are inferred from mixed flow measurement techniques. Such computer programs are used in the optimization and safety analysis of nuclear plants, as well as maintaining an acceptable materials balance in coal conversion plants. Knowledge of individual phase flow velocities will benefit computer programs in which all equations are written for individual phase flow velocities. Also, in the area of nuclear reactor design and operation, knowledge of individual phase velocities in circular pipes can be used through known extrapolation techniques to predict reactor core phenomena such as pressure and the departure of nuclear boiling regimes.
To date, cross-correlation of signals from thermocouples, impedance probes, accoustic transducers, and various other devices has been used to determine mixed phase flow velocities. The cross-correlation method works well in homogeneous single-phase media, but it is ill-suited for non-homogeneous multi-phase flow conditions since only a "transport" mixed phase velocity (i.e., an average velocity somewhere between the liquid phase and gas-phase flow velocities) is rendered by the cross-correlation method. There is no method known to date by which the mixed-phase velocity value can be related to one or more individual phase flow velocities. The same shortcoming is experienced in systems having solid/gas and solid/liquid as well as liquid/gas multiphase flows.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.